1. Field of the Invention
This invention relates to a radio frequency environment monitoring system for object presence feedback. More particularly, the invention relates to a radio frequency environment monitoring system for RFID tagged and/or untagged object monitoring via analysis of changes to the monitored RF environment occurring as the objects present in the monitored area are varied in position and or number.
2. Description of Related Art
Previous RFID tag inventory and or object passage gateway monitoring systems have relied upon reading one or a plurality of tags, each tag representing a unit or known quantity of units of associated objects.
It is not practical to apply an RFID tag to each object to be monitored, and/or it is desirable to monitor the presence of quantities of the objects to be monitored with greater precision than just a binary indication of an RFID tag associated with a quantity of objects each of which may or may not be tagged, as might be the case with items contained in a parts bin.
In prior RFID portal systems, RFID readers monitor RFID tags attached to objects and/or object loads during passage through, for example, a number of dock doors in a distribution center. Because of the nature of known RFID systems it is not always possible to determine whether particular tags are in a particular door. It is possible for example for a reader in door 2 to read a tag in door 1 or door 3. Without special door sensors, it is not possible to determine whether a particular door is open or closed and whether an object is moving out of the distribution center or into the distribution center.
Further, many items have packaging that is not complementary to being tagged, such as metal cans and/or plastic bottles, such as soft drinks. Also, it is not economical to tag individual items, such as nails, bolts, batteries, coins or the like. To optimize inventory operations, for example for Just In Time inventory systems, it is required to know the rate of depletion and/or when inventory of a specific item is about to be depleted, before actual depletion occurs.
Therefore, it is an object of the invention to provide an object monitoring solution that overcomes deficiencies in the prior art.